An apparatus for in-line holographic imaging is disclosed. In one aspect, the apparatus includes at least a first light source and a second light source arranged for illuminating an object arranged in the apparatus with a light beam. The apparatus also includes an image sensor arranged to detect at least a first and a second interference pattern, wherein the first interference pattern is formed when the object is illuminated by the first light source and the second interference pattern is formed when the object is illuminated by the second light source. The first and second interference patterns are formed by diffracted light, being scattered by the object, and undiffracted light of the light beam. The at least first and second light sources are arranged at different angles in relation to the object, and possibly illuminate the object using different wavelengths.